Random numbers

I made a procedure where when the mob dies one of two possible mobs is supposed to spawn in it's place. Thing is, while the code looks fine and the game launches fine i always get the same mob every time I kill it. It's an if else command with the two options being the 2 mob spawns and it's "if (random [0,1]) = (1)", i don't see why that shouldn't work. I can post a screenshot if need be.